i have the same problem for a few weeks now. the back ups is dead (apc pro-1500, 5 or 6 years old only).... I can't record anything without clicks and static spike noises now... What would you recommend ?

i have the same problem for a few weeks now. the back ups is dead (apc pro-1500, 5 or 6 years old only).... I can't record anything without clicks and static spike noises now... What would you recommend ?

Isn't it just the battery that would be dead ?
So, since your ups is dead, you removed it and now, you have click noise ?

But not any audio dedicated filter (which are much more expensive for, I bet, the same thing inside...) Take care to the Ampère value ! It's around I=P/U, so for a 10A filter, the max power should be around P=UI = 240x10 = 2400W, in reality, it's a bit more complicated but this method gives you an idea of what filter you should find (if you know what power there is on your supply !).

the battery is dead but I haven't removed the ups yet, I must move a whole bunch of furniture to access the wall plug.
I will put a phase reversable plug first ( Schuko plug), then something else.

As I haven't removed the back ups, it could be something else, but it coincides in timing. Then I found this thread which describes the exact same problem so it could be that. What is certain is that the electricty is not great where i am now, i know it can be better.
Will keep you posted when solved.

I haven't really looked at hifi stuff for so long - looks like some cool products nowadays....including Marantz etc. Been so caught up in DAW / recording hi-tech over the last decades I forgot about this kinda stuff.

I would take care with that kind of hifi shop ! Some people can spend fortunes for improving the sound quality ! They know that and sale cheap devices 10 times the price ! Or even useless gear.
For instance, hifi fans buy cables which carry only digital data 10 times more expensive and they are convinced the sound is better ! But it's digital data, not analog ! And of course, the cable manufacturer says what hifi crazy people want to hear !

Anyway... I would check the sound after removing the ups before to buy any filter ! As the issue happend exactly at the same time it stoped to work, I bet it's the cause.